Telescopic vacuum-cleaner wand

ABSTRACT

A vacuum-cleaner wand has an inner tube extending along an axis, having a substantially cylindrical outer surface, and formed with an axially extending row of radially outwardly open latch pockets forming radially inwardly projecting bumps. A middle tube extending along the axis surrounds the inner tube, has a substantially cylindrical inner surface riding on the inner-tube outer surface, and is formed with an axially extending row of radially outwardly projecting latch bumps. The inner and middle tubes are generally devoid of structure projecting from their outer and inner surfaces along most of their length. A latch body axially fixed on the middle tube is radially displaceable into and out of the outwardly open inner-tube pockets. A latch on the middle tube shifts the middle-tube latch body radially into the inner-tube pockets to lock the inner and outer tubes relative to each other.

FIELD OF THE INVENTION

The present invention relates to a vacuum-cleaner wand. More particularly this invention concerns such a wand that can telescopically extend.

BACKGROUND OF THE INVENTION

The telescopic suction wand for a vacuum cleaner disclosed in EP 1 033 103 of Kittelman is especially advantageous due to relatively low production and assembly costs. Nonetheless this known telescopic suction wand for a vacuum cleaner appears in need of improvement as regards its longitudinal adjustment.

Similarly the three-part telescopic wand of U.S. Pat. No. 5,836,620 of Wang is a relatively complex structure with a gear rack provided on the side of the middle and inner tubes for latching the tubes together. The whole assembly has a fairly large radial thickness to accommodate the complex latch structure, and is fairly expensive to manufacture.

OBJECTS OF THE INVENTION

It is therefore an object of the present invention to provide an improved telescopic vacuum-cleaner wand.

Another object is the provision of such an improved telescopic vacuum-cleaner wand that overcomes the above-given disadvantages, in particular that is of simple inexpensive construction, that can move from a very short to a fairly long condition, and that is of relatively slim construction.

SUMMARY OF THE INVENTION

A vacuum-cleaner wand has an inner tube extending along an axis, having a substantially cylindrical outer surface, and formed with an axially extending row of radially outwardly open latch pockets forming radially inwardly projecting bumps. A middle tube extending along the axis surrounds the inner tube, has a substantially cylindrical inner surface riding on the inner-tube outer surface, and is formed with an axially extending row of radially outwardly projecting latch bumps. The inner and middle tubes are generally devoid of structure projecting from their outer and inner surfaces along most of their length. A latch body axially fixed on the middle tube is radially displaceable into and out of the outwardly open inner-tube pockets. A latch on the middle tube shifts the middle-tube latch body radially into the inner-tube pockets to lock the inner and middle tubes together and out of the inner-tube pockets for relative telescoping of the inner and middle tubes. An outer tube extending along the axis surrounds the middle tube. A latch body axially fixed on the outer tube is radially displaceable into and out of engagement with the outwardly projecting middle-tube bumps. A latch on the outer tube shifts the outer-tube latch body radially into engagement with the middle-tube pockets to lock the middle and outer tubes together and out of the middle-tube pockets for relative telescoping of the middle and outer tubes.

With this design, the latch pockets of the inner tube and the middle-tube latch pockets may move collision-free past one another by means of a telescopic movement so as not to prevent retractability, e.g. when reducing the length of the total device on account of packaging requirements.

At the same time, the middle-tube latch pockets opening radially outwardly from the middle-tube outer surface allow for the installation of the third or outer tube, which may be provided with the same latch element—at least based on its operational principle—as the outer tube.

Overall, the telescopic wand for a vacuum cleaner according to the invention has optimal optional shortening of the total wand device in addition to a large extension length with a plurality of individual axial adjustment options.

In a further embodiment of the invention, the latch pockets of the inner tube and the middle-tube latch pockets are arranged in the same radial plane, that is they are radially aligned with each other. This arrangement allows for ergonomically favorable handling along the same line of the wand.

A further advantageous variant of the invention is that the latch pockets of the inner tube and the middle-tube latch pockets are axially aligned with one another when both latch elements are in their latching positions. This arrangement is important also with reference to the wand seal of the inner tube located at the end, in that the length of the inner tube is such that the wand seal with its seal face is located in the wand wall area of the outer tube that is undeformed with reference to the middle-tube latch pockets, thus ensuring a uniform seal. In other words, when the inner tube is latched in the middle tube (and when the middle tube is latched in the outer tube) the inner-tube (or middle-tube) rear or top end is aligned between the pockets of the surrounding tube so as to form a good annular seal therewith. Otherwise there might be some leak.

According to the invention the latch pockets of the inner tube and of the middle latch are differently spaced. The latch pockets of the inner tube normally have a smaller spacing that allows for individual fine adjustment when performing suction work, whereas the comparatively larger spacing of the middle-tube latch pockets may allow for adjustment according to the height of the person using the vacuum cleaner.

In the extreme case, the spacing of the outer tube may be designed such that the outer tube has only two latch pockets, one being adjacent to the respective latch element and the other arranged at the opposite end of the middle tube, remote from the latch element.

It should be furthermore added that adjacent middle-tube pocket there is an outwardly projecting bump having a part-cylindrical outer surface that rides on the cylindrical inner surface of the outer tube. Thus the outer tube slides smoothly on the middle tube on the inner tube.

BRIEF DESCRIPTION OF THE DRAWING

The above and other objects, features, and advantages will become more readily apparent from the following description, reference being made to the accompanying drawing in which:

FIG. 1 is a side view of a three-piece telescopic wand for a vacuum cleaner in collapsed position;

FIG. 2 is a top view of the wand of FIG. 1;

FIG. 3 is an axial section taken along line III-III of FIG. 2;

FIG. 4 is an enlarged view of the detail indicated in FIG. 3 at IV;

FIGS. 5 and 6 are views like respective FIGS. 1 and 2 with the wand extended;

FIG. 7 is an axial section taken along line VII-VII of FIG. 6; and

FIG. 8 is an enlarged view of the detail indicated in FIG. 7 at VIII.

SPECIFIC DESCRIPTION

A telescopic wand 10 for a vacuum cleaner has an inner tube 12, a coaxial middle tube 11 fitted over the inner tube 12, and an outer tube 13 fitted over the middle tube 11, all generally of cylindrical shape and extending along a common axis A. The tubes 11, 12, and 13 are of uniform wall thickness, normally made of light metal or plastic. Air is sucked rearwardly through the wand 10 in the direction of arrow y. Normally a brush or other tool is fitted to the front (right-hand in the drawing) end of the outer tube 13 and the rear (left-hand in the drawing) end of the inner tube 12 is fitted to the vacuum-cleaner suction hose.

The inner tube 12 has a cylindrical outer surface 14 formed with latch pockets 15 projecting radially inward toward and open radially outward away from the wand axis M, with no structure projecting outward from the surface 14 of the tube 12.

The middle tube 11 has an inner face 35 that slides smoothly and fits with the outer surface 14 of the inner tube 12 and is formed with a row of outwardly projecting bumps 31 spaced apart by latch pockets 16 opening radially outward from a middle-tube outer surface 17 and from the wand axis M. There is no structure projecting inward from the surface 35 of the middle tube 11, and the inner diameter of the surface 35 is only slightly greater than the outer diameter of the surface 14 for smooth sliding and no leakage between the tubes 11 and 12.

The additional telescopic outer tube 13 overlapping the middle tube 11 has no latch pockets, and its overall shape is cylindrical and smooth except for a longitudinal inwardly open groove accommodating the bumps 31. All the tubes 11, 12 and 13 have, at least substantially, a circular-cylindrical cross-section.

The middle tube 11 is provided with a latch element 18 at its rear end 19, while the outer tube 13 at its rear end 20 is provided with its own latch element 21. Both latch elements 18 and 21 are substantially identical, so that for components that work in an analogously similar or identical way, the same reference numbers apply.

Each latch element 18 and 21 is locked by means of an axial guide sleeve 22 in the respective wand end 19 and 20. The respective guide sleeve 22 forms a retaining block or body 24 whose shape is adapted to the guide sleeve 22 in a dust-tight way by means of a flexible retaining guide sleeve 23. Each guide sleeve 22 is overlain by a control sleeve 25 that is movable axially back and forth in opposite axial directions x and z against the spring force of a roughly partial-ring rod spring 26 mounted on the external casing surface of the relevant guide sleeve 22. The end of the motion of each rod spring 26, which is carried along axially by the control sleeve 25, is seen in FIG. 4.

As shown in the drawings, a retaining projection 27 holds the retaining body 24 in its latching position. If axial adjustment of the wand 10 is intended, the control sleeve 25 needs only be pushed in one of the directions x or z, so that the retaining body 24 attached pivotally to the guide sleeve 22 by means of the retaining guide 23 and formed with escape spaces 28 may pivot up and out of its latched position and into its unlatched position. Once unblocked by the body 27, an axial force applied to one of the tubes relative to the other will cam out the block 24 and allow the tubes to be relatively axially shifted.

To prevent relative rotation of the middle tube 11 and the inner tube 12, the guide sleeve 22 in the middle tube 11 has a radially outwardly projecting key or spline formation 29 that engages axially and slidably in an axially inwardly open groove 30 formed in the inner tube 12. Formations identical to the key 29 and groove 30 can be provided in the middle tube 11 and inner tube 12.

As can be seen from the drawings, the latch pockets 15 of the inner tube 12 according to the shown embodiment and the middle-tube latch pockets 16 of the middle tube 11 have the same spacing. In this case, it is important to dimension the length of the end 32 of the inner tube 12 such that the inner end seal 34 thereof engages a seal region 33 of the inner tube 12 and falls when the tubes 11 and 13 are relatively latched at annularly continuous or cylindrical wall area 35 of the middle tube 11 between the oblong-rectangular guide bumps 31. 

1. A vacuum-cleaner wand comprising: an inner tube extending along an axis, having a substantially cylindrical outer surface, and formed with an axially extending row of radially outwardly open latch pockets forming radially inwardly projecting bumps; a middle tube extending along the axis, surrounding the inner tube, having a substantially cylindrical inner surface s riding on the inner-tube outer surface, and formed with an axially extending row of radially outwardly projecting latch bumps; a latch body axially fixed on the middle tube and radially displaceable into and out of the outwardly open inner-tube pockets; latch means on the middle tube for shifting the middle-tube latch body radially into the inner-tube pockets to lock the inner and middle tubes together and out of the inner-tube pockets for relative telescoping of the inner and middle tubes; an outer tube extending along the axis and surrounding the middle tube; a latch body axially fixed on the outer tube and radially displaceable into and out of engagement with the outwardly projecting middle-tube bumps; and latch means on the outer tube for shifting the outer-tube latch body radially into engagement with the middle-tube pockets to lock the middle and outer tubes together and out of the middle-tube pockets for relative telescoping of the middle and outer tubes.
 2. The vacuum-cleaner wand defined in claim 1 wherein the middle tube is of uniform radial wall thickness between the respective pockets and at the inner faces of the respective pockets.
 3. The vacuum-cleaner wand defined in claim 1 wherein the rows of the middle-tube pockets and of the outer-tube pockets are radially aligned with each other.
 4. The vacuum-cleaner wand defined in claim 1 wherein the rows of the middle-tube pockets and of the outer-tube pockets are radially aligned with each other in when the latch bodies are engaged in the respective pockets.
 5. The vacuum-cleaner wand defined in claim 1 the inner tube has a front end inside the middle tube and the inner tube and its pockets are dimensioned relative to the middle tube that when the middle-tube latch body is engaged in one of the inner-tube pockets the inner-tube front end sits between pockets of the middle tube.
 6. The vacuum-cleaner wand defined in claim 1 wherein the inner-tube pockets are spaced axially differently from the middle-tube bumps.
 7. The vacuum-cleaner wand defined in claim 6 wherein the inner-tube pockets are more closely spaced axially than the middle-tube bumps.
 8. The vacuum-cleaner wand defined in claim 1 wherein the middle tube has only two pockets, one adjacent each end of the middle tube.
 9. The vacuum-cleaner wand defined in claim 1 wherein the middle tube is formed between the bumps with inwardly open pockets.
 10. The vacuum-cleaner wand defined in claim 1 wherein the inner tube is generally devoid of structure projecting from its outer surface along most of its length, and the middle tube is generally devoid of structure projecting from its inner surface along most of its length. 